1. Field of the Invention
This invention relates to a multifrequency piezoelectric horn system, and, particularly, to an electronic horn including a piezoelectric vibrator for generating audible sound and for use in automobiles.
2. Description of the Prior Art
In automobiles, electromagnetic horns have commonly been used which include an electromagnetic mechanism, which may cause the horns to be heavy and massive, to consume electric power remarkably, and to be a source of noises, such as surge voltage, to electronics involved in the cars in which the electromagnetic horns are equipped.
Piezoelectric vibrators or sound generators, such as buzzers, generate simple harmonic acoustic waves at the range of two or three kilohertz, which may not be comfortable to the ear. With commonly available piezoelectric buzzers, the sound energy level of 90 db was measured at the distance of one meter in front of them. Both tone and energy level of the sound were therefore not suitable for horns for use in automobiles. For electronic horns for use in cars, it is required to generate audible sound of a broader bandwidth giving a sufficient sound pressure to other cars and pedestrains around the cars.
It is therefore an object of the present invention to provide a multifrequency piezoelectric horn system which is light, consumes small electric power, nor is harmful to other electronics.
It is another object of the invention to provide a multifrequency piezoelectric horn system which generates audible sound having sufficiently suitable tone and energy level for automobiles.